Communication cables comprised of multiple twisted pairs of conductors are common, with four-pair cables being widely used. In a four-pair cable, the twisted pairs of conductors may in turn be twisted around a central axis of the cable. The length of cable in which one complete twist of the twisted pairs is completed around the cable's central axis is considered the “core lay length” of the cable. For example, if the twisted pairs complete one rotation around the central axis of the cable every six inches, the core lay length of the resulting cable is six inches.
A communication channel may comprise a communication cable with connectors at the ends of the cable. Suppression of crosstalk in and between communication channels is important, because crosstalk can reduce the signal-to-noise ratio in a channel and increase the channel's bit error rate. Power-sum alien near-end crosstalk (“PSANEXT”) between channels can be caused by common-mode noise introduced into the channels at connectors. This common mode noise is relative to one conductor pair within a channel, and the common mode noise has its greatest impact when adjacent cables have identical core lay lengths. As communication bandwidth increases, the reduction of crosstalk between channels becomes increasingly important.